Software products are currently typically distributed to end users on optically encoded discs, such as compact disc-read only memory (CD-ROM) discs or digital versatile discs (DVDs). Because of the complexity of some software products and the number of routines, objects, components, functions, data structures, modules, and libraries included with the product, it is not uncommon for the products to require from several hundred megabytes (MB) to several gigabytes (GB) of total storage on the distribution discs. Electronic games, which often include complex graphic files and sound libraries, may require both layers on a DVD to store all of the files on a single disc.
The placement of files on a storage medium can sometime affect the efficiency with which the files are read from the drive. On DVDs, data are encoded such that each data block is the same linear size. Since the circumference of a single data track is longer nearer the outer edge of the disc, more data are recorded nearer the outer edge per track or rotation than nearer the inner portion. Drives of the constant linear velocity type (CLV) rotate more slowly as data are read from tracks closer to the outer edge, and speed up to read data from tracks nearer the inner portion of the disc. In contrast, on drives of the constant angular velocity (CAV) type, files placed nearer the outer edge of a DVD are read faster than those placed nearer the center. So, if read with a drive of the CAV type, to most efficiently load the files of a game or other software program from a disc into random access memory (RAM), a developer will preferably order the files as they are stored on the disc so that those files that must be loaded first to initiate display of a start screen and other frequently accessed files are stored closest to the outer edge of the disc. Also, files that are sequentially loaded into memory are preferably placed close together to minimize the seek time of the disc drive to access and read the files. The developer can list the files in the order that they should preferably be stored on the disc, from the outermost edge toward the center, to achieve the most efficient access of files needed during loading and execution of the software product.
A growing problem faced by companies that distribute and license software on CD-ROMs or DVDs is the ease with which such software can be duplicated for resale in violation of the copyright in the product. Various techniques have been developed to reduce the risk of copying such discs. Game software distributed on discs that are used on a game console is particularly at risk of being copied. One technique that has been developed to prevent copying uses security placeholders that divide a DVD into a plurality of segments. The security placeholders are written onto the discs in a manner that is difficult to duplicate using conventional disc copying techniques. For example, DVD software discs used with Microsoft Corporation's X-BOX™ game console employ a security format that uses eight placeholders to divide each layer of a dual layer DVD into nine segments in which files may be stored. The placeholders are positioned on the DVD according to predefined rules and a pseudo random variable is applied to slightly change the position of the placeholders relative to their initial position determined by these predefined rules. Files stored on a secure disc produced using this format must be placed in the available 3.2 GB of storage per layer provided in the 18 segments defined by the placeholders. The sizes of the segments are not fixed, but instead, typically vary from one DVD to another. Although the placeholders can be moved from their initial position, any change in position must be done in an automated manner, in accord with the predefined rules, which are not made known to a developer.
Manually laying out the storage of files on a secure DVD format that uses placeholders to divide a disc into segments, so that the files are arranged in a desired order, can be a time consuming and relatively inefficient task, since the user cannot manually move the placeholders to fit files into segments. Accordingly, it would be preferable to automate the layout of the files on such a disc by providing a software tool for automatically laying out the files of a software product within the segments of a secure disc. The tool should enable a user to add, delete, and move files within the segments on the secure disc using a file management program, and should then adjust the disposition of the files in the layout by segments accordingly.